Engine Coolant Temperature Sensor 2 Circuit High
What does P2185 mean?
The P2185 code means the vehicle's onboard diagnostic system has detected: Engine Coolant Temperature Sensor 2 Circuit High. This is a moderate severity code.
Common Symptoms
- Temperature gauge reading abnormally cold
- Engine running rich (excess fuel)
- Cooling fans not turning on
- Poor fuel economy
- Check engine light on
Probable Causes (Ranked by Likelihood)
- Faulty engine coolant temperature sensor 2 (open circuit) Very High
- Disconnected or corroded ECT sensor 2 connector High
- Open circuit in ECT sensor 2 wiring Moderate
- ECT sensor 2 reference voltage shorted to signal Moderate
- PCM input circuit failure Low
Step-by-Step Diagnostic Procedure
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Check ECT sensor 2 connector -- ensure it is plugged in and free of corrosion
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Measure ECT sensor 2 resistance -- should be approximately 2,500 ohms at 68F and 300 ohms at 176F
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With sensor disconnected, check signal wire for voltage -- should see 5V reference if wiring is intact
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Compare ECT sensor 2 reading to ECT sensor 1 on scan tool -- they should be close when engine is warm
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Replace ECT sensor 2 if resistance is out of specification
Frequently Asked Questions
Can I drive with code P2185?
You can drive short distances, but the PCM may use a default temperature value that causes rich fuel mixture, poor fuel economy, and the cooling fans may not activate properly. Monitor the temperature gauge for signs of overheating.
Why does my car have two coolant temperature sensors?
Many modern vehicles have two ECT sensors. One provides temperature data to the PCM for fuel and ignition calculations, while the other may feed the instrument cluster gauge, cooling fan control, or serve as a backup. Some vehicles use both sensors for more accurate temperature monitoring.
What does circuit high mean for a temperature sensor?
ECT sensors have negative temperature coefficient (NTC) -- their resistance decreases as temperature increases. A high voltage (circuit high) means high resistance, which the PCM interprets as a very cold reading. This is typically caused by an open circuit, disconnected sensor, or a sensor that has failed open.